6.4. Loading Missing Firmware

As described in Section 2.2, “Devices Requiring Firmware”, some devices require
firmware to be loaded. In most cases the device will not work at all
if the firmware is not available; sometimes basic functionality is not
impaired if it is missing and the firmware is only needed to enable
additional features.

If a device driver requests firmware that is not available, debian-installer will
display a dialog offering to load the missing firmware. If this option
is selected, debian-installer will scan available devices for either loose firmware
files or packages containing firmware. If found, the firmware will be
copied to the correct location (/lib/firmware) and
the driver module will be reloaded.

Note

Which devices are scanned and which file systems are supported depends on
the architecture, the installation method and the stage of the installation.
Especially during the early stages of the installation, loading the firmware
is most likely to succeed from a FAT-formatted floppy disk or USB stick.
On i386 and amd64 firmware can also be loaded from an
MMC or SD card.

Note that it is possible to skip loading the firmware if you know the
device will also function without it, or if the device is not needed during
the installation.

debian-installer only prompts for firmware needed by kernel modules loaded during
the installation. Not all drivers are included in debian-installer, in particular
radeon is not, so this implies that the capabilities of some devices may
be no different at the end of the installation from what they were at
the beginning. Consequently, some of your hardware may not be being used
to its full potential. If you suspect this is the case, or are just
curious, it is not a bad idea to check the output of the
dmesg command on the newly booted system and search
for “firmware”.

6.4.1. Preparing a medium

Official CD images do not include non-free firmware. The most common
method to load such firmware is from some removable medium such as a USB
stick. Alternatively, unofficial CD builds containing non-free firmware
can be found at http://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/.
To prepare a USB stick (or other medium like a hard drive partition, or floppy
disk), the firmware files or packages must be placed in either the root directory
or a directory named /firmware of the file system on
the medium. The recommended file system to use is FAT as that is most
certain to be supported during the early stages of the installation.

Tarballs and zip files containing current packages for the most common firmware are
available from:

Just download the tarball or zip file for the correct release and unpack it to
the file system on the medium.

If the firmware you need is not included in the tarball, you can also
download specific firmware packages from the (non-free section of the)
archive. The following overview should list most available firmware
packages but is not guaranteed to be complete and may also contain
non-firmware packages:

It is also possible to copy individual firmware files to the medium. Loose
firmware could be obtained for example from an already installed system or
from a hardware vendor.

6.4.2. Firmware and the Installed System

Any firmware loaded during the installation will be copied automatically
to the installed system. In most cases this will ensure that the device
that requires the firmware will also work correctly after the system is
rebooted into the installed system. However, if the installed system runs
a different kernel version from the installer there is a slight chance that
the firmware cannot be loaded due to version skew.

If the firmware was loaded from a firmware package, debian-installer will also install
this package for the installed system and will automatically add the non-free
section of the package archive in APT's sources.list.
This has the advantage that the firmware should be updated automatically if
a new version becomes available.

If loading the firmware was skipped during the installation, the relevant
device will probably not work with the installed system until the firmware
(package) is installed manually.

Note

If the firmware was loaded from loose firmware files, the firmware copied to
the installed system will not be automatically updated
unless the corresponding firmware package (if available) is installed after
the installation is completed.